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APOD: The ISS over Earth (2016 Apr 18)
Posted: Mon Apr 18, 2016 4:06 am
by APOD Robot
The International Space Station over Earth
Explanation: The
International Space Station is the largest object ever constructed by humans in space. The
station perimeter extends over roughly the area of a
football field, although only a small fraction of this is composed of modules habitable by humans. The
station is so large that it could not be
launched all at once -- it continues to be built
built piecemeal. To function, the
ISS needs huge
trusses, some over 15 meters long and with masses over 10,000 kilograms, to keep it rigid and to route
electricity and liquid
coolants.
Pictured above, the immense
space station was photographed from the now-retired
space shuttle Atlantis after a week-long stay in 2010. Across the image top hangs part of a bright blue
Earth, in stark contrast to the darkness of
interstellar space across the bottom.
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Re: APOD: The ISS over Earth (2016 Apr 18)
Posted: Mon Apr 18, 2016 7:19 am
by madtom1999
I notice the solar panels are not all pointing in the same direction. Is this to help control generation to match demand or are the being used like solar sails to guide the craft?
Re: APOD: The ISS over Earth (2016 Apr 18)
Posted: Mon Apr 18, 2016 9:01 am
by geckzilla
madtom1999 wrote:I notice the solar panels are not all pointing in the same direction. Is this to help control generation to match demand or are the being used like solar sails to guide the craft?
They actually increase drag depending on which direction they are facing as the ISS travels through the very, very thin atmosphere. They may be in a transitional state from one of the modes they run in to help reduce this drag.
https://en.wikipedia.org/wiki/Night_Glider_mode
Or, who knows, maybe they were being flipped around so that astronauts on the space shuttle could visually inspect them. I don't suppose anyone from mission control might be around to offer any other suggestions or a definitive answer.
Re: APOD: The ISS over Earth (2016 Apr 18)
Posted: Mon Apr 18, 2016 2:27 pm
by Chris Peterson
madtom1999 wrote:I notice the solar panels are not all pointing in the same direction. Is this to help control generation to match demand or are the being used like solar sails to guide the craft?
There can be many things going on. They feather the panels when spacecraft are nearby to reduce forces on the ISS from thruster exhaust (which is probably the most common reason we see them that way in outside pictures). They change their angles to manage demand. They change them to avoid certain shadows from the ISS structures. The motors don't all run at the same maximum rate, so during changes they can be at different angles.
Re: APOD: The ISS over Earth (2016 Apr 18)
Posted: Mon Apr 18, 2016 2:28 pm
by Asterhole
It's quite an impressive structure, and more keeps being added on.
Re: APOD: The ISS over Earth (2016 Apr 18)
Posted: Mon Apr 18, 2016 2:35 pm
by Fred the Cat
While walking last night shortly after sunset in Idaho looking up to see the
Moon and Jupiter conjunction there was a bright light just south of the two heading East. We followed it for a very long period of time; around 5 minutes, and suspected it was a chance run-in with ISS in the sky.
It was only listed as very short appearance last night on "
Spot the Station". It wasn't even listed on
Heavens Above until I clicked on "All Passes". We are about 5 miles north and west of the listed city - Boise. It really appeared much brighter and for much longer than the listed sighting.
On "Spot the Station" for (Sun Apr 17, 8:54 PM < 1 min 15° 15° above SE 10° above SE) it lists the pass-over as a brief appearance and it wasn't even shown as a visible pass on Heavens Above which we have set to our city's coordinates. It seems like these sites were not "in conjunction" with our visible observation. Any ideas?
Re: APOD: The ISS over Earth (2016 Apr 18)
Posted: Mon Apr 18, 2016 9:38 pm
by Boomer12k
What an awesome shot... so beautiful...
I FINALLY hit good weather, and have gotten out the 10" Meade. Check out my post in the other forum...
The Asterisk Café: Discuss Anything Astronomy Related:
Latest pics...from Boomer12k.
Hope that was alright to post that...
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